/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Public/GameplayEffect.h
Attempts to calculate the magnitude of the captured attribute given the specified parameters, up to the specified evaluation channel (inclusive). Can fail if the spec doesn't have a valid capture yet.
True if the magnitude was successfully calculated, false if it was not
bool AttemptCalculateAttributeMagnitudeUpToChannel ( const [FAggregatorEvaluateParameters](API\Plugins\GameplayAbilities\FAggregatorEvaluateParameters) & InEvalParams, [EGameplayModEvaluationChannel](API\Plugins\GameplayAbilities\EGameplayModEvaluationChannel) FinalChannel, float & OutMagnitude ) const